Category:
Lightweight scooter, personal urban transport.
Competitors:
Competed with other 50cc scooters of the era from brands like Honda (e.g., Aero 50), Suzuki (e.g., FZ50), and Tomos.
Vehicle Characteristics:
User-friendly operation, economical, easy to maneuver in urban environments, often favored by younger riders or for short commutes.
Value:
Essential tool for owners seeking to maintain, repair, or restore their classic Yamaha QT50, enabling cost savings and extending vehicle lifespan.
Primary Coverage:
Full Service, Repair, Maintenance, Rebuild, Refurbish, Restoration
Estimated Page Count:
Comprehensive (exact number not specified, but described as 'very detailed')
Type:
Service Repair Manual
Format:
Likely digital (PDF) given typical sales of manuals, but print possibility exists.
Engine System:
Complete engine overhaul, disassembly, assembly, lubrication, cooling, fuel, ignition, exhaust.
Transmission System:
Automatic transmission (CVT) maintenance, repair, and adjustment procedures.
Chassis System:
Frame, suspension (front and rear), steering, wheels, and tires.
Braking System:
Front drum brake and rear drum brake systems, including component inspection, adjustment, and replacement.
Electrical System:
Ignition system, lighting, charging system, wiring diagrams, component testing.
Fuel System:
Carburetor adjustment, cleaning, and overhaul; fuel tank and lines.
Bodywork And Trim:
Body panels, fairings, seat, storage compartments, fenders, and associated hardware.
Routine Maintenance:
Oil changes, lubrication, filter replacement, spark plug service, drive belt inspection.
Troubleshooting:
Diagnostic procedures for common and uncommon issues, fault finding charts.
Component Rebuild:
Detailed steps for rebuilding engine, carburetor, transmission, and other mechanical components.
Assembly And Disassembly:
Step-by-step instructions for taking apart and putting back together various vehicle systems.
Wiring Diagrams:
Complete electrical system schematics with component identification.
Depth:
Comprehensive, covering all aspects from basic maintenance to complete engine and transmission overhauls.
Engine Type:
2-stroke, air-cooled
Bore X Stroke:
37.0 mm x 42.0 mm
Horsepower:
Approx. 3.2 HP @ 6000 RPM (Varies slightly by market and tuning)
Torque:
Not widely specified, typically modest for its class.
Carburetor Model:
Mikuni VM16-32 (typical, confirmation in manual is key)
Fuel Type:
Unleaded gasoline (min. 87 octane) mixed with 2-stroke oil
Fuel Oil Ratio:
50:1 (Standard for most Yamaha 2-strokes of this era, confirm in manual)
Oil Type:
Yamalube 2-stroke oil or equivalent API TCW-II or TCW-III rated oil.
Ignition System:
CDI (Capacitor Discharge Ignition)
Spark Plug:
NGK B7HS or equivalent (Gap: 0.6-0.7 mm)
Type:
Automatic CVT (Continuously Variable Transmission) with V-belt drive.
Drive Type:
Shaft drive (typically for scooters of this era, but chain drive also possible - manual to confirm).
Gear Reduction:
Automatic, providing seamless gear changes across the operational range.
Overall Length:
Approx. 1700 mm (66.9 in)
Overall Width:
Approx. 660 mm (26.0 in)
Overall Height:
Approx. 1050 mm (41.3 in)
Wheelbase:
Approx. 1190 mm (46.9 in)
Dry Weight:
Approx. 68 kg (150 lbs)
Gross Vehicle Weight Rating Gvwr:
Not typically specified for this class, but general load capacity applies.
Crash Test Results:
N/A (Scooters of this era did not undergo standardized crash testing like automobiles.)
Lighting:
Headlight, tail light, brake light, turn signals.
Braking Control:
Mechanical drum brakes front and rear. Parking brake function typically absent.
Structural Reinforcement:
Frame constructed for basic rider support.
Oil Change:
Every 1,000-2,000 km (600-1,200 miles) or annually, depending on usage (confirm specific interval in manual).
Air Filter Cleaning Or Replacement:
Every 1,000-3,000 km (600-1,800 miles) or as needed based on operating conditions.
Spark Plug Cleaning Or Replacement:
Every 2,000-4,000 km (1,200-2,400 miles).
Drive Belt Inspection And Replacement:
Inspect every 3,000 km (1,800 miles), replace as needed or every 6,000-10,000 km (3,600-6,000 miles).
Transmission Oil Type:
Yamaha Gear Oil SAE 80W or equivalent API GL-4 rated hypoid gear oil. Capacity: Approx. 0.08 Liters.
Brake Fluid Type:
DOT 3 (for hydraulic systems, if applicable, but drum brakes are mechanical) - confirm if any hydraulic components exist.
Carburetor Clogging:
Common in older 2-stroke scooters due to fuel degradation and oil residue, requiring regular cleaning.
Cvt Belt Wear:
Normal wear and tear, leading to slipping or reduced acceleration. Belt replacement is standard maintenance.
Ignition System Reliability:
CDI units can sometimes fail with age, leading to no spark. Spark plugs and ignition coils are common service items.
Air Leaks:
Leaking intake manifold gaskets or crank seals can cause rich running conditions or poor idle quality.
Yamaha Motor Corporation:
Founded in 1955, Yamaha Motor Corporation has a long history in motorcycles, marine products, and other powered vehicles, known for innovation and performance.
Qt Series:
The QT series represented Yamaha's entry into the lightweight scooter market, focusing on practicality and affordability.
Production Period:
The QT50 was produced through the 1980s, with minor updates across its lifespan. The 1985 model represents a mid-production variant.
